Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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LOFT LADDER ASSEMBLY
FIELD OF THE INVENTION
The present invention relates to a loft ladder
assembly.
BACKGROUND OF THE INVENTION
Hatch doors are commonly provided in a ceiling to
allow access to the loft or roof space of a building. Loft
ladders are also known which are stored in the roof space
and which are deployed by being pulled down after the hatch
door has been opened.
Conventional loft ladders are usually of the
extendable type. This means that the ladder is formed of
two (or sometimes three) ladder sections arranged in
different planes, which can slide over one another and can
be locked to each other in a stacked and in an extended
position. Even after the sections have been stacked, they
are longer than the hatch door. Consequently, to stow away
the ladder, it first has to be raised into the loft and
then pivoted for its lower end to be able to pass through
the hatch. The stacked ladder is normally pivoted about an
axis, which is near its centre so that the ladder is nearly
balanced. As a result, the ladder tends to stay in its
horizontal position in the loft when the hatch door is
opened and, to deploy it, a user must first pivot its lower
end of the hatch and then release its various catches
manually to allow it to be extended to reach the floor.
Because such ladders are not very compact, even in
their stacked condition, they have the disadvantage of
taking up roof space. It is therefore preferable to form
the ladder as a telescopically collapsible ladder where the
stiles are formed of sections that collapse into one
another, as described for example in EP-B1-0 527 766. Such
a ladder is more compact than an extendable ladder when it
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is collapsed and can be made sufficiently small to fit
entirely within the hatch opening.
However, if the top rung of a telescopically collapsible
ladder is pivoted on one side of the hatch opening, it will
tend to drop and extend itself under the action of its own
weight as soon as the hatch door is opened. This could cause
injury to an unsuspecting user.
SUMMARY OF THE INVENTION
The present invention therefore seeks to provide a loft
ladder assembly that can fit within a hatch opening without
taking up loft space and can be deployed and stowed away
simply and safely.
According to the present invention, there is provided a
loft ladder assembly for accessing a loft through a hatch
opening, where the loft ladder assembly comprises a
telescopically collapsible ladder having a locking arrangement
being releasable on one rung to collapse the ladder and a
frame for mounting the ladder within the hatch opening, the
frame comprising a mounting bracket to be secured in use to
the hatch opening, connecting arrangements to pivotably
connect the ladder to the frame and holding arrangements to
hold the ladder in relation to the frame when the ladder is in
a collapsed position, wherein the ladder is provided with
corresponding holding arrangements, which interact with the
holding arrangements on the frame characterized in that beams
are pivotably connected to the frame, and in that an uppermost
section of the ladder is pivotably connected to the beams by
the connecting arrangements.
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To prevent the ladder from extending under the action of
its own weight, the carriage may be provided with means for
releasably engaging the lowermost section of the ladder. The
latter means may suitably comprise a pair of hooks for
receiving lugs projecting laterally from the lowermost section
of the ladder.
Preferably, the carriage is connected to the mounting
bracket by means of at least one spring urging the carriage
into the stowage position against the action of the weight of
the ladder. Conveniently, each spring should be connected to
the mounting bracket and the carriage in such a manner as to
act as an over-centre toggle spring, so as
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to urge the carriage away from the ladder when the latter
is deployed.
The collapsible ladder is preferably constructed in
the manner taught by EP-B1-0 527 766. In particular, the
ladder may have locking pins built into the rungs that are
spring biases to move laterally outwards into holes formed
in the stiles to lock the sections of the stiles together
when the ladder is in its extended position, the locking
pins for the next higher section of the ladder being
retracted as the rung carrying the locking pins approaches
the rung beneath it. When constructed in this manner, the
ladder will open naturally from the top downwards when its
lowermost section is released from the carriage and it will
collapse in sequence from the lowermost section upwards as
it is raised into its stowage position.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described further, by way
of example, with reference to the accompanying drawings, in
which:
Fig. 1 is a perspective view of a first embodiment of
a loft ladder assembly of the present invention in its
stowage position;
Fig. 2 is a side view of the loft ladder assembly in
Fig. 1;
Fig. 3 is a side view of the loft ladder assembly
with the carriage lowered into a vertical position;
Fig. 4 is a view similar to that of Fig. 3 with the
ladder in its deployed position;
Fig. 5 is a perspective view of a second embodiment
of a loft ladder assembly of the present invention in a
partially lowered position;
Fig. 6 is a view similar to that of Fig. 5 with the
ladder in its deployed position;
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Fig. 7 is a side view of the loft ladder assembly in
Fig. 6;
Fig. 8 is a perspective view of a third embodiment of
a loft ladder assembly of the present invention in its
stowage position;
Fig. 9 is a side view of the loft ladder assembly in
Fig. 8;
Fig. 10 is a perspective view of the loft ladder
assembly of Fig. 8 in a partially lowered position;
Fig. 11 is a side view of the loft ladder assembly of
Fig. 8 with the carriage lowered into a vertical position;
Fig. 12 is a view similar to that of Fig. 11 with the
ladder in its deployed position;
Fig. 13 is a perspective view of a fourth embodiment
of a loft ladder assembly of the present invention in its
stowage position; and
Fig. 14 is a side of the loft ladder assembly of Fig.
13 with the ladder in its deployed position.
DETAILED DESCRIPTION OF THE EMBODIMENTS
A first embodiment of a loft ladder assembly 10 is
shown in Fig. 1, which comprises a telescopically
collapsible ladder 12 and a frame 14 for mounting the
ladder in a hatch opening. The frame 14 is formed of a
mounting bracket 14a and a carriage 14b pivotable relative
to the mounting bracket 14a between a horizontal position
shown in Fig. 1 and a vertical position shown in Figs. 3
and 4. Two coil springs 16a and 16b act as toggle springs,
as will be described below, to spring bias the carriage 14b
into its two end positions.
The hatch opening is partially shown in Figs. 1- 14
with three of the walls 40 forming the hatch opening. The
frame 14 is mounted on one of the walls 40 in the shown
embodiments, but could also be mounted on the hatch door.
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The ladder 12 is constructed in the same manner as a
conventional telescopic ladder, which is currently
commercially available under the trademark Telesteps .
Whilst such a construction of the ladder is preferred, it
5 is not fundamental to the present invention and it will not
therefore be described in detail in the present context.
For further details on the internal construction of the
ladder 12, reference may be made to EP-B1-0 527 766.
The Telesteps ladder is preferred because it
collapses from the bottom upwards and not from the top
downwards. In particular, the ladder has locking pins built
into its rungs, which are spring biased to move laterally
outwards into holes formed in the stiles in order to lock
the sections of the stiles together when the ladder is in
its extended position. As two rungs come together, the
lower rung presses on two levers 26 (shown of the second
lowermost rung of Fig. 13) which depend from the upper rung
to cause the locking pins formed in the upper rung to be
retracted from the stiles. This now allows the next higher
section of the ladder to be collapsed and the process
repeats until all the sections are collapsed from bottom
upwards.
Each of the rungs of the ladder has two laterally
projecting lugs 24, which engage in hooks 22 projecting
from the carriage 14b. After the ladder has been fully
collapsed, the lugs 24 of the second lowermost rung 33 can
be lifted onto the hooks 22 and this prevents the ladder
from extending under the action of its own weight.
The uppermost section of the ladder is pivoted
relative to the mounting bracket 14a about pins 28 passing
two limbs 20 that project from the mounting bracket 14a.
Similarly, the carriage 14b is pivoted about pins 18
passing through two short ears 30 that project from the
mounting bracket 14a.
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The springs 16a and 16b are connected to bracket 14a
and the carriage 14b in such a manner that as the carriage
pivots downwards from the horizontal position shown in Fig.
1 to the vertical position shown in Fig. 2, it passes
through an over-centre position in which the ends of the
spring and the pivot pins 18 lie in a straight line. In
this position, the length of the spring is maximized and a
force has to be applied to the carriage to move the
carriage towards this position, as the position is
approached in either direction. In other words, the springs
16a and 16b have a toggle action forcing the carriage 14b
away from the over-centre position. Thus, the carriage is
stably held by the springs 16a and 16b in both the
horizontal and the vertical positions.
In use, the ladder assembly is fixed by securing the
mounting bracket 14a by bolts or screws to the ceiling
joists surrounding and defining the hatch opening. When the
hatch door 60 (only shown in Figs. 12-14) is opened by
being hinged or removed, the loft ladder assembly will be
found in the hatch opening in its configuration shown in
Fig. 1. In this state, the springs apply a moment to the
carriage 14b, which is slightly greater than the moment of
the combined weights of the ladder 12 and the carriage 14b,
so that the loft ladder assembly will remain in the hatch
opening after the hatch door has been opened.
To deploy the ladder, the carriage 14b is pivoted
downwards against the action of the springs 16a and 16b by
pulling down on a strap 32 (shown in Figs. 3 and 4). This
operation does not require much effort because of the
leverage afforded by the carriage 14b. The carriage is
pivoted past the over-centre position to the position shown
in Figs. 3 and 4, from which it will be seen that the line
of action of the springs 16a and 16b has moved to the
opposite side of the pins 18 so that the carriage 14b will
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now remain stable in its vertical position without
assistance from the weight of the ladder 12.
When the ladder is stowed away, there remains a
distance between its top two rungs. This allows the user to
lift the entire ladder and thereby disengage the lugs 24
from the hooks 22. Once the weight of the ladder 12 is no
longer supported by the hooks 22, it will extend naturally
from the top downwards as can be seen in Fig. 4. This
allows the user to pull the ladder 12 away from the
carriage 14b and to extend until it reaches the ground and
is inclined at a safe and comfortable angle.
To stow away the ladder, the above procedure is
essentially reversed. First after using the levers 26
(partially shown in Figs. 1 and 4) to release the locking
pins of the second lowermost rung 33 of the ladder, the
lowermost section (comprising the rungs 33 and 35) of the
ladder is raised. As the rung 33 reaches the next higher
rung, it will automatically release the locking pins of the
next higher ladder section to collapse that ladder section.
The process is repeated until the entire ladder is
collapsed.
With all the sections of the ladder 12 collapsed
against one another, the lugs 24 of the second lowermost
rung 33 can be raised onto the hooks 22 whereupon the
weight of the ladder will be fully supported by the
carriage 14b. While holding the strap 32 (only shown in
Figs. 3 and 4), the carriage can now be pivoted towards its
horizontal position and once it passes the over-centre
position the strap 32 is used to restrain the ladder so
that it can be returned gently to its stowage position of
Fig. 1. The hatch door can then be replaced or closed.
In Figs. 5-7 a second embodiment of the loft ladder
assembly 10 is shown, where the arrangement for holding the
ladder 12 in the stowage position is formed by a hook
section 122 provided on the lowermost rung 35. The hook
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section receives in the stowage position (shown in Fig. 5)
a vertical bar 50 of the carriage 14b, which extends
between the horizontal bars 51 and 52 of the carriage 14b.
Apart from the holding arrangement the loft ladder assembly
according to the second embodiment is operated in the same
manner as the loft ladder assembly according to the first
embodiment.
In Figs. 8 -12 a third embodiment of the loft ladder
assembly 10 is shown, which is intended to be used in hatch
openings where the ladder cannot be accommodated in the
hatch opening, but needs to be stored in the loft above the
hatch opening. The loft ladder assembly shown in Figs. 8-12
has a similar arrangement for holding the ladder 12 in the
stowage position as the loft ladder assembly shown in Figs.
5-7, i.e. a hook section 122 is provided on the lowermost
rung 35 to receive the vertical bar 50 of the carriage 14b.
The loft ladder assembly of Fig. 8-12 is further
provided with L-shaped beams 70, which are pivotably
connected to brackets 14a in a first end 70 and having the
ladder 12 pivotably connected in a second end 71. The beams
70 enable an upper part of the ladder 12 to extend over the
hatch opening so that the ladder 12 can be stowed away even
though the ladder 12 is longer than the hatch opening. This
is shown in Figs. 8 and 9.
To deploy the ladder, the carriage 14b is pivoted
downwards against the action of the springs 16a and 16b by
pulling down on a strap. This operation does not require
much effort because of the leverage afforded by the
carriage 14b. The beams 70 and the carriage 14b are pivoted
past the over-centre position (see Fig. 10) to the position
shown in Fig. 11, from which it appears that the line of
action of the springs 16a and 16b has moved to the opposite
side of the pins 18 so that the carriage 14b will now
remain stable in its vertical position without assistance
from the weight of the ladder 12.
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From this position the user lifts the entire ladder
and thereby disengages the hooks 122 from the bar 50 and
the beams 70 are pivoted further. Once the weight of the
ladder 12 is no longer supported by the bar 50, it will
extend naturally from the top downwards similar to what can
be seen in Fig. 4. This allows the user to pull the ladder
12 away from the carriage 14b and to extend until it
reaches the ground and is inclined at a safe and
comfortable angle. The beams 70 will typically be pivoted
to the position shown in Fig. 14.
To stow away the ladder, the above procedure is
essentially reversed. First after using the levers on the
second lowermost rung 33 of the ladder 12 to release the
locking pins, the ladder is raised. As the rung 33 reaches
the next higher rung, it will automatically release the
locking pins of the next higher ladder section to collapse
that ladder section. The process is repeated until the
entire ladder is collapsed.
With all the sections of the ladder 12 collapsed
against one another, the hook 122 of the lowermost rung 35
can be placed onto the bar 50 whereupon the weight of the
ladder will be fully supported by the carriage 14b. While
holding the strap, the beams and the carriage can now be
pivoted towards its horizontal position and once it passes
the over-centre position the strap is used to restrain the
ladder so that it can be returned gently to its stowage
position of Figs. 8 and 9. The hatch door 60 can then be
replaced or closed.
In Figs. 13 and 14 a fourth embodiment of the loft
ladder assembly 10 is shown, which is intended to be used
in hatch openings where the ladder cannot be accommodated
in the hatch opening, but needs to be stored in the loft
above the hatch opening. The loft ladder assembly shown in
Figs. 13 and 14 is similar to the third embodiment of the
loft ladder assembly shown in Figs. 8-12, but without the
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carriage and the springs. The arrangement for holding the
ladder 12 in the stowage position is similar to that of the
second and the third embodiment, but the hook 122 is
provided on the second lowermost rung 33 and a vertical bar
5 90 is received. The vertical bar 90 is mounted on braces
114a of the frame 14. The beams 70 are pivotably mounted on
the bar 90.
In the stowage position as shown in Fig. 13 the
weight of the upper part of the ladder 12, i.e. the part of
10 the ladder 12 which extend over the hatch opening, secures
that the ladder will remain in the stowage position. When
the hatch door 60 is opened the ladder 12 will remain in
the stowage position. To deploy the ladder the user pulls a
strap connected to the lowermost rung and the beams 70 and
the ladder 12 are pivoted past the over centre position to
a horizontal position.
From this position the user lifts the entire ladder
and thereby disengages the hooks 122 from the bar 50 and
the beams 70 are pivoted further. Once the weight of the
ladder 12 is no longer supported by the bar 50, it will
extend naturally from the top downwards similar to what can
be seen in Fig. 4. This allows the user to pull the ladder
12 and to extend it until it reaches the ground and is
inclined at a safe and comfortable angle. The beams 70 will
typically be pivoted to the position shown in Fig. 14.
To stow away the ladder, the above procedure is
essentially reversed. First after using the levers on the
second lowermost rung 33 of the ladder 12 to release the
locking pins, the ladder is collapsed. As the rung 33
reaches the next higher rung, it will automatically release
the locking pins of the next higher section to collapse
that ladder section. The process is repeated until the
entire ladder is collapsed.
With all the sections of the ladder 12 collapsed
against one another, the beams can now be pivoted towards
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its horizontal position and once it passes the over-centre
position the hook 122 of the lowermost rung can be placed
onto the bar 50 whereupon the weight of the ladder will be
fully supported by the frame 14. The strap is used to
restrain the ladder so that it can be returned gently to
its stowage position of Fig. 13. The hatch door 60 can then
be replaced or closed.
The lower part of the ladder 12 can also be
releasably connected to the hatch door 60 so that the
ladder 12 will pivot as the hatch doors opens.
The person skilled in the art will appreciate that
various modifications may be made to the described loft
ladder assembly without departing from the scope of the
invention as set out in the appended claims. For example,
the carriage 14b may carry or be connected to the hatch
door. Furthermore, in place of springs, one could use a
catch to hold the carriage in its raised position.
